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Friday, May 3, 2013

What happened to antimatter? - Rolf Landua

Me and Rolf Landua holding the antimatter container of DaVinci's Code

Do you remember the antimatter bomb in the DaVinci's Code movie?

In my journey at CERN, Rolf Landua gave a lecture about antimatter. Basically the topics in the lecture was this questions: What is it? Where is it create? How can be created? What is the mystery behind it? How can we study it? Can we use it as a energy font or a bomb? Is any antimatter in our daylife?

In particle physics, antimatter is material composed of antiparticles, which have the same mass as particles of ordinary matter but have opposite charge and quantum spin. Antiparticles bind with each other to form antimatter in the same way that normal particles bind to form normal matter. For example, a positron (the antiparticle of the electron, with symbol e+) and an antiproton (symbol p) can form an antihydrogen atom. Furthermore, mixing matter and antimatter can lead to the annihilation of both, in the same way that mixing antiparticles and particles does, thus giving rise to high-energy photons (gamma rays) or other particle–antiparticle pairs. The end result of antimatter meeting matter is a release of energy proportional to the mass as the mass-energy equivalence equation, E=mc2 shows.

At this time, the apparent asymmetry of matter and antimatter in the visible universe is one of the greatest unsolved problems in physics.

Antimatter is created in the LHC, and the LHCb is the detector responsible to detect particles in the antiprotons' collisions. The antiprotons' production is achieved with the collisions between protons and nucleus of Iridium, Cupper, and others. The antiprotons are decelerated and keep trapped with a combination of electric and magnetic fields (so it doesn't touch matter). In this way, the resultant material is detected by the detector before the annihilation. That event is one of the biggest mysteries of the Big Bang, and scientist are trying to answer it: the domination of the matter over the antimatter.

FDG is a glucose molecule, with fluorine-18 attached

This antimatter cannot be used as energy or weapon because we need energy to create it. Imagine that we want to produce 0.5 g of antimatter. Well, we need 22 kton (22,000 ton) of TNT (almost the same value of the Hiroshima's bomb), to produce 0.5 g of matter and antimatter. The energy in this process is about 4.5 x 1013 J. The total energy that we need (because the efficiency is 10-9 %) will be 4,5 x 1022 J. Even with CERN's discount made by French Electric Company [1 kwh = 3,6 x 106 J= 0,1 €], the total cost will be 1 x 108 € and it will be take a billion years to produce and supply this production to CERN.

But, antimatter is used in our body for PET scan detection. The glucose has a fluorine-18 attached that will emit positrons when that molecule travels in our body, and the scanner detects where the positrons go.

The next step that scientist at CERN are trying to develop is to use positrons and antiprotons as therapy in some deceases.